Synthesis ⇝ Noise Colors

Most people have heard of white noise, but there's more than one color of noise and the different types have specific definitions.

White Noise is random noise that has equal energy at all frequencies.

Pink Noise is similar to white noise, but with a 3 decibel drop in power per octave, making the bass frequencies stronger.

Brown Noise is similar to pink noise, but with a 6 decibel drop in power per octave, making the bass frequencies stronger. It is also referred to as Brownian noise or red noise, and can be generated with a Brownian-motion-based algorithm.

Blue Noise is the inverse of pink noise, with a 3 decibel increase in power per octave, making the treble frequencies stronger. This is also referred to as azure noise.

Purple Noise is the inverse of brown noise, with a 6 decibel increase in power per octave, emphasizing the higher frequencies more. This is also referred to as violet noise.

Grey Noise is similar to white noise, but with a psychoacoustic filter applied so it sounds like there is equal energy at all frequencies. The Human ear does not hear all frequencies equally, so this filtering adjusts the random noise to take the ear's frequency response into account.

Black Noise is another name for silence.